Alt-BEAM Archive
Message #00693
To: beam@corp.sgi.com
From: Terry Newton wtnewton@nc5.infi.net
Date: Sat, 20 Feb 1999 11:15:30
Subject: [alt-beam] Re: hmmm...i wonder which subject
At 12:04 PM 2/20/99 +0100, Steven Bolt wrote:
>It seems to me that a little uC can perform all relevant functions
>of the microcore above - but why bother, and yes, it would be less
>cool :)
Oh, I'll bother, I do plan to make a uP walker but only for
convenience, so I can try all sorts of different timings without
building a bunch of stuff. I want to try coupled bicores and the
Stills/Tilden arrangement where the microcore is saturated.
Just to try, not to be cool, not to make it smart...
>five-motor `Walkman' is by far the most sensible configuration for
>any experiment involving Nervous Net stuff. If you want no more
>than two motors, something like my Spider is superior - walks and
>turns easily and predictably.
I'm pretty sure your Spider a linear-drive robot, just not using
wheels. Being linear, it should match very well with machine learning.
How is the spider on rough terrain? Do you offer the spider
chassis in a kit? I'd love to get one.
>> Like a hard-wired reversing obstacle avoiding photovore. Being able
>> to back up makes all the difference in the world. Someone's gotta
>> do a (beam) photopopper that backs up,
>
>Hey! My three photovores all back up nice and dandy, and they
>don't even have reversable motors.
no offense... I meant an updated circuit for the classic-shaped
photopopper with shaft-table drive pager motors. Something that
looks like a little car... you know! robot-looking.
>> a pair of h-bridges and some minor logic, shouldn't be that
>> difficult.
>
>Easier than you think, actually. No h-bridges required:
>
> Linkname: Photovore - search the light, avoid obstacles
> URL: http://arlene.xs4all.nl/WWW/e-fotovoor_beweging.html
(the url's wrong but I found it) It doesn't seem to have a front
and back, no need to reverse because it can't get in that position.
I think this was one of the first 'beam' photovores I ever encountered,
an excellent example of solving the problem with mechanics. Actually
the stock Solarbotics photopopper can be quite avoiding if the feelers
are shaped just right... so it'll always have enough radius to turn
around. But then it occupies a fairly large area. I want to see a
real reversible photopopper that can maneuver through tight spots
and not get stuck. Like my picbot can, but in analog.
I'm thinking glue a couple zetex smd h-bridge chips to the back of
a stock photopopper along with a bit of logic powered by its own
diode/cap so it'll stay hot through the complete discharge. Behavior
would be if both feelers touch, or either feeler touches for too
long (very simple learning?), switch the 1381 outs to the opposite
motor reversing inputs with a 4053 or similar. Going the mod route
it would have to be really small and efficient, smd all the way.
Maybe even with a hardwired associative memory? Noam Rudnick's
post was interesting, now I'm thinking about crossed inverters
and stable states...
Terry Newton
------------------------------------------------------------------------
eGroup home: http://www.eGroups.com/list/alt-beam
Free Web-based e-mail groups by eGroups.com
Home